Resource-efficient beam selection in 5G and 6G

ABSTRACT

Communications in 5G and 6G can use “beams” to focus electromagnetic energy on the recipient, and the recipient can likewise arrange a focused reception “beam” toward the transmitter, thereby saving energy and avoiding interference. However, aligning the transmission and reception beams remains an arduous process. Herein, procedures are disclosed for rapid and efficient beam alignment at both transmission and reception devices, using very brief response signals to select an optimal beam direction for best signal quality. By encoding the selected beam index in the time, frequency, and optionally modulation of the brief signal, the transmitter and receiver can cooperate to optimize communication and save energy.

PRIORITY CLAIMS AND RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 63/278,578, entitled “Location-Based Beamformingfor Rapid 5G and 6G Directional Messaging”, filed Nov. 12, 2021, andU.S. Provisional Patent Application Ser. No. 63/342,437, entitled“Resource-Efficient Beam Selection in 5G and 6G”, filed May 16, 2022,all of which are hereby incorporated by reference in their entireties.

FIELD OF THE INVENTION

The disclosure pertains to wireless beamforming, and more particularlyto means for selecting an optimum beam direction.

BACKGROUND OF THE INVENTION

In 5G and 6G, many communications are carried out using “beams” ordirected radiation, aimed at the intended recipient. A complextime-consuming procedure is required to align the beams in the rightdirections. What is needed is a simpler, more efficient procedure forselecting an optimal beam direction.

This Background is provided to introduce a brief context for the Summaryand Detailed Description that follow. This Background is not intended tobe an aid in determining the scope of the claimed subject matter nor beviewed as limiting the claimed subject matter to implementations thatsolve any or all of the disadvantages or problems presented above.

SUMMARY OF THE INVENTION

In a first aspect, there is a method for a base station of a wirelessnetwork to align a beam from the base station to a user device of thenetwork, the method comprising: transmitting a plurality of beam scansignals, each beam scan signal comprising a wireless transmissionfocused in a different direction, the beam scan signals spaced apart intime or in frequency; receiving, from the user device, a reply signalindicating a particular beam scan signal, the reply message comprising awireless transmission at a time corresponding to a time of theparticular beam scan signal or at a frequency corresponding to afrequency of the particular beam scan signal; and transmitting, to theuser device, a subsequent message directed according to the particularbeam scan signal.

In another aspect, there is a user device of a wireless networkcomprising a base station, the user device configured to: receive aplurality of beam scan signals, each beam scan signal transmitted in adifferent direction by the base station, the beam scan signals spacedapart in time or in frequency; measure a signal quality of each beamscan signal, the signal quality comprising an amplitude, a power level,or a signal-to-noise ratio; determine a particular beam scan signalhaving a best or highest signal quality; determine a particular time ora particular frequency associated with the particular beam scan signal;and transmit, to the base station, a reply signal indicating theparticular time or the particular frequency.

In another aspect, there is non-transitory computer-readable media in abase station of a wireless network comprising a user device, the mediacontaining instructions that, when executed in a computing environment,cause a method to be performed, the method comprising: transmitting aplurality of beam scan signals, each beam scan signal having the sameamplitude and phase, and each beam scan signal transmitted in adifferent direction, wherein the beam scan signals occupy sequentialsymbol-times or sequential subcarriers of a resource grid defined by thenetwork; monitoring a reply window comprising a predetermined region ofthe resource grid following the beam scan signals, and detecting atleast one reply signal in the reply window; determining, according to atime or a frequency of the at least one reply signal, a particular beamscan signal; determining, according to the particular beam scan signal,a particular geographical direction; and transmitting, to the userdevice, a geographical direction message indicating the particulargeographical direction.

This Summary is provided to introduce a selection of concepts in asimplified form. The concepts are further described in the DetailedDescription section. Elements or steps other than those described inthis Summary are possible, and no element or step is necessarilyrequired. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended foruse as an aid in determining the scope of the claimed subject matter.The claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

These and other embodiments are described in further detail withreference to the figures and accompanying detailed description asprovided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic showing an exemplary embodiment of a requestmessage from a user device to a base station, according to someembodiments.

FIG. 1B is a schematic showing an exemplary embodiment of a beam scanfrom a base station to a user device, according to some embodiments.

FIG. 1C is a schematic showing an exemplary embodiment of a replymessage from a user device to a base station, according to someembodiments.

FIG. 1D is a schematic showing an exemplary embodiment of an alignmentmessage from a base station to a user device, according to someembodiments.

FIG. 1E is a schematic showing an exemplary embodiment of anacknowledgement message from a user device to a base station, accordingto some embodiments.

FIG. 2A is a sequence chart showing an exemplary embodiment of anefficient transmission beam scan from a base station to a user device,according to some embodiments.

FIG. 2B is a sequence chart showing an exemplary embodiment of anefficient reception beam scan by a user device, according to someembodiments.

FIG. 2C is a flowchart showing an exemplary embodiment of a procedurefor base stations and user devices to align their beams, according tosome embodiments.

FIG. 3A is a schematic showing a resource grid with an efficienttime-spanning beam selection, according to some embodiments.

FIG. 3B is a schematic showing a resource grid with time-spanning beamalignment messages for multiple users, according to some embodiments.

FIG. 3C is a flowchart showing an exemplary embodiment of atime-spanning procedure for base stations and multiple user devices toalign their beams, according to some embodiments.

FIG. 4A is a schematic showing an exemplary embodiment of an efficientfrequency-spanning beam selection, according to some embodiments.

FIG. 4B is a schematic showing an exemplary embodiment of an efficientfrequency-spanning beam selection for multiple users, according to someembodiments.

FIG. 4C is a flowchart showing an exemplary embodiment of afrequency-spanning procedure for base stations and multiple user devicesto align their beams, according to some embodiments.

FIG. 5A is a schematic showing another exemplary embodiment of anefficient frequency-spanning beam selection, according to someembodiments.

FIG. 5B is a schematic showing another exemplary embodiment of anefficient frequency-spanning beam selection for multiple users,according to some embodiments.

FIG. 5C is a flowchart showing an exemplary embodiment of a simplerprocedure for base stations and multiple user devices to align theirbeams, according to some embodiments.

FIG. 6 is a flowchart showing an exemplary embodiment of a procedure foraligning beam directions, according to some embodiments.

FIG. 7 is a schematic showing a resource grid with an efficient beamselection and direction information, according to some embodiments.

FIG. 8 is a flowchart showing another exemplary embodiment of aprocedure for aligning beam directions, according to some embodiments.

FIG. 9 is a schematic showing a resource grid with an efficient beamselection for user devices that lack beamforming, according to someembodiments.

FIG. 10 is a flowchart showing another exemplary embodiment of aprocedure for user devices that lack beamforming, according to someembodiments.

Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION

Systems and methods disclosed herein (the “systems” and “methods”, alsooccasionally termed “embodiments” or “arrangements” or “versions”,generally according to present principles) can provide urgently neededwireless communication protocols for aligning directional transmissionbeams and reception beams to improve communication quality. Instead ofwasting time and resources on a multi-step handshaking procedure, thetransmitter and receiver can cooperate to select the best beam directionat both ends efficiently, starting with no knowledge of their relativepositions.

To assist user devices in aligning their beams, and to align the basestation beams toward the user devices, a base station can first transmita scheduling message informing user devices of a planned beam scan, oralternatively a user device can transmit a request message requestingbeam alignment service. In either case, the base station then transmitsa series of brief “beam scan” signals in a sequence of directions. Auser device can monitor the beam scan signals using a non-directionalantenna, and can determine which signal provides the best reception. Theuser device can then emit a brief reply signal at a particular timeand/or frequency corresponding to the best-quality beam signal, againusing a non-directional antenna for transmission. The base station canreceive the reply signal at a particular time or frequency correspondingto the favored beam scan signal, and can determine, from the particulartime or frequency, which transmission beam produced the best receptionfor that user device. Then, the base station may transmit an “alignment”message consisting of several resource elements, all at the same powerlevel. The user device can receive the alignment message while varyingits reception beam directions, and thereby determine which receptionbeam provides the best reception for that user device. Thus the basestation and the user device have aligned their transmission andreception beams toward each other, thereby completing the beamconfiguration at both ends.

Often there are multiple user devices that need beam alignment service,in which case they can all measure the beam scan signals, determinewhich beam works best for each user device, and transmit a reply messageon separate pre-assigned subcarriers or symbol-times. The base stationwill know, according to the time and frequency of each reply signal,which user device desires which beam setting. In addition, the basestation can transmit one alignment message non-directionally, or it cantransmit a plurality of alignment messages each in the direction of oneof the user devices. The user devices can receive the alignment messagewhile varying their reception beam directions, and thereby determine theoptimal beam direction toward the base station for each user device.Then, each user device can transmit an acknowledgement and/or achannel-state information message, using the recently-determined optimalbeam direction of the user device, while the base station receives themessage using the beam direction selected by each user device.

Optionally, the beam scan signals can be configured as a single resourceelement for compactness, or as two resource elements carrying areference signal, or other number of resource elements. Optionally, thereply message may be a single resource element, or as two or moreresource elements conveying additional information, and may be modulatedto carry yet additional information. Optionally, the user device cantransmit two reply signals instead of one, thereby indicating two of thebeam scan signals, and the base station can interpolate between theindicated beams to provide a beam direction with higher precision.Optionally, the acknowledgement could include additional information,such as an indication of the signal quality determined by the userdevice, so that the base station can then adjust its transmission powerlevel. The base station can also instruct the user device regarding theuser device's power levels, for example. Optionally, the same beamselection process could be carried out in reverse, with the user deviceproviding the beam scan signals in different directions, and the basestation selecting the best transmission beam, followed by the userdevice transmitting an alignment message while the base station variesits reception beam direction and selects the best reception beam.Optionally, two user devices (such as vehicles in traffic) can aligntheir beams toward each other without base station involvement, bycarrying out the disclosed procedures in sidelink.

User devices and base stations, by aligning their transmission andreception beams using the disclosed resource-efficient procedures, canrapidly and efficiently gain improved communications with less energyconsumption, less background radiation and interference due to the lowertransmission power levels and reduced angular spread, and can therebyimprove network performance generally, according to some embodiments.

“Reciprocity” is assumed throughout, in the sense that the same beamdirection is optimal for both reception and transmission purposes, andthe same spatial trajectory is optimal for both the user device and thebase station.

Terms herein generally follow 3GPP (third generation partnershipproject) standards, but with clarification where needed to resolveambiguities. As used herein, “5G” represents fifth-generation, and “6G”sixth-generation, wireless technology in which a network (or cell or LANLocal Area Network or RAN Radio Access Network or the like) may includea base station (or gNB or generation-node-B or eNB or evolution-node-Bor AP Access Point) in signal communication with a plurality of userdevices (or UE or User Equipment or user nodes or terminals or wirelesstransmit-receive units) and operationally connected to a core network(CN) which handles non-radio tasks, such as administration, and isusually connected to a larger network such as the Internet. Thetime-frequency space is generally configured as a “resource grid”including a number of “resource elements”, each resource element being aspecific unit of time termed a “symbol period” or “symbol-time”, and aspecific frequency and bandwidth termed a “subcarrier” (or “subchannel”in some references). Symbol periods may be termed “OFDM symbols”(Orthogonal Frequency-Division Multiplexing) in references. The timedomain may be divided into ten-millisecond frames, one-millisecondsubframes, and some number of slots, each slot including 14 symbolperiods. The number of slots per subframe ranges from 1 to 8 dependingon the “numerology” selected. The frequency axis is divided into“resource blocks” (also termed “resource element groups” or “REG” or“channels” in references) including 12 subcarriers, each subcarrier at aslightly different frequency. The “numerology” of a resource gridcorresponds to the subcarrier spacing in the frequency domain.Subcarrier spacings of 15, 30, 60, 120, and 240 kHz are defined invarious numerologies. Each subcarrier can be independently modulated toconvey message information. Thus a resource element, spanning a singlesymbol period in time and a single subcarrier in frequency, is thesmallest unit of a message. “Classical” amplitude-phase modulationrefers to message elements modulated in both amplitude and phase,whereas “PAM” (pulse-amplitude modulation) refers to separatelyamplitude-modulating two signals and then adding them with a 90-degreephase shift. The two signals may be called the “I” and “Q” branchsignals (for In-phase and Quadrature-phase) or “real and imaginary”among others. Standard modulation schemes in 5G and 6G include BPSK(binary phase-shift keying), QPSK (quad phase-shift keying), 16QAM(quadrature amplitude modulation with 16 modulation states), 64QAM,256QAM and higher orders. Most of the examples below relate to QPSK or16QAM, with straightforward extension to the other levels of modulation.QPSK is phase modulated but not amplitude modulated. 16QAM may bemodulated according to PAM which exhibits two phase levels at zero and90 degrees (or in practice, for carrier suppression, ±45 degrees) andfour amplitude levels including two positive and two negative amplitudelevels, thus forming 16 distinct modulation states. For comparison,classical amplitude-phase modulation in 16QAM includes four positiveamplitude levels and four phases of the raw signal, which aremultiplexed to produce the 16 states of the modulation scheme.Communication in 5G and 6G generally takes place on abstract message“channels” (not to be confused with frequency channels) representingdifferent types of messages, embodied as a PDCCH and PUCCH (physicaldownlink and uplink control channels) for transmitting controlinformation, PDSCH and PUSCH (physical downlink and uplink sharedchannels) for transmitting data and other non-control information, PBCH(physical broadcast channel) for transmitting information to multipleuser devices, among other channels that may be in use. In addition, oneor more random access channels may include multiple random accesschannels in a single cell. “CRC” (cyclic redundancy code) is anerror-checking code. “RNTI” (radio network temporary identity) is anetwork-assigned user code. “SNR” (signal-to-noise ratio) and “SINR”(signal-to-interference-and-noise ratio) are used interchangeably unlessspecifically indicated. “RRC” (radio resource control) is a control-typemessage from a base station to a user device. “Digitization” refers torepeatedly measuring a waveform using, for example, a fast ADC(analog-to-digital converter) or the like. An “RF mixer” is a device formultiplying an incoming signal with a local oscillator signal, therebyselecting one component of the incoming signal.

In addition to the 3GPP terms, the following terms are defined herein.Although in references a modulated resource element of a message may bereferred to as a “symbol”, this may be confused with the same term for atime interval (“symbol-time”), among other things. Therefore, eachmodulated resource element of a message is referred to as a “modulatedmessage resource element”, or more simply as a “message element”, inexamples below. A “demodulation reference” is a set of Nref modulated“reference resource elements” or “reference elements” modulatedaccording to the modulation scheme of the message and configured toexhibit levels of the modulation scheme (as opposed to conveying data).Thus integer Nref is the number of reference resource elements in thedemodulation reference. A “calibration set” is one or more amplitudevalues (and optionally phase values), which have been determinedaccording to a demodulation reference, representing the predeterminedmodulation levels of a modulation scheme. Thus the receiver candetermine modulation levels from one or more demodulation reference,calculate intermediate levels by interpolation if needed, and thenrecord the modulation levels in the calibration set. Each modulationlevel in the calibration set may have a code or number associated withit, and the receiver can demodulate the message element by selecting themodulation level in the calibration set that most closely matches theobserved modulation level of the message element, and then assigningthat associated code or number to the message element. If the messageelement has more than one modulation level, such as amplitude and phase,then the two associated codes or numbers may be concatenated to form thedemodulated message element. Generally the modulation scheme includesinteger Nlevel predetermined amplitude or phase levels. “RF” orradio-frequency refers to electromagnetic waves in the MHz (megahertz)or GHz (gigahertz) frequency ranges. A “sum-signal” is a waveformincluding the combined signals from a plurality of separately modulatedsubcarriers. A “short-form demodulation reference” is a compactdemodulation reference exhibiting, generally, the maximum and minimumamplitude or phase levels of a polarization scheme so that the receivercan calculate other levels by interpolation. A “beam” is a directedelectromagnetic transmission or reception signal, as opposed to anisotropic or non-directional transmission or reception. A “transmissionbeam” is a spatially narrow or focused energy transmission, and a“reception beam” is a spatially narrow sensitivity or focused efficiencydistribution in a reception antenna (usually, the same physical antennacan be used for both transmission and reception). Beams may be generatedby multi-element antennas using analog or digital electronic controls.“Reciprocity” is assumed herein, whereby the signal path from the basestation to the user device is the same as the signal path from the userdevice to the base station, and an optimal beam direction fortransmission is the same as an optimal beam direction for reception.“Alignment” of a transmission or reception beam by a first wirelessentity in communication with a second wireless entity means determininga direction at which the first entity can aim its beam to optimize thesignal quality obtained by the second wireless entity. “Non-directionalmeans isotropic, or at least uniform in a horizontal plane.

Turning now to the figures, a first example shows, schematically,signals between a user device and a base station to select optimal beamsat both ends.

FIG. 1A is a schematic showing an exemplary embodiment of a requestmessage from a user device to a base station, according to someembodiments. As depicted in this non-limiting example, a base stationantenna 101, viewed from the top, is in communication with a user device102, depicted as a mobile phone. The user device 102 transmits a requestmessage 104. The request message 104 is configured to initiate a beamscan procedure as disclosed herein. The request message 104 istransmitted non-directionally, as indicated by the nested circles. Therequest message 104 propagates from the user device 102 to the basestation 101 as indicated by an arrow 105. The base station 101 monitorsthe channel or frequency of the signal 104 using a non-directionalreceptivity 103 of the antenna 101, as indicated by dashed arcs.

In these figures, distributions of transmitted energy are indicated bysolid lines such as 104, while reception sensitivity distributions areindicated by dashed lines such as 103. Directional beams are indicatedby narrow ovals, and non-directional distributions by nested arcs. Sincethe user device 102 and the base station 101 do not initially know eachother's location, in this example, they both employ non-directionalcommunication distributions for transmitting and receiving the requestmessage 105.

As an alternative, the base station can initiate the process bytransmitting a scheduling message (not shown) to the user device,indicating a time and frequency at which the beam selection messageswill appear. As a third alternative, the user device can request it andthe base station can then schedule it in response. As a fourthalternative, the beam alignment process may be triggered automaticallywhen a new user device joins the network. Other preparatory messages mayalso be employed to coordinate the two entities.

FIG. 1B is a schematic showing an exemplary embodiment of a beam scanfrom a base station to a user device, according to some embodiments. Asdepicted in this non-limiting example, the base station antenna 111 andthe user device 112 are as described previously, but now the basestation 111 is transmitting and the user device 112 is receiving.Responsive to the request message 105, (or the scheduling message orjoining the network, etc.) the base station transmits a series of brief“beam scan” signals, each beam scan signal transmitted on separatetransmission beam directions 113, thereby covering a range of directionswith separate signals. The transmission beam scan signals 113 may bespaced apart in time or in frequency. The beam scan signals 113propagate from the base station 111 to the user device 112 as indicatedby an arrow 115. The user device 112 monitors the channel at apredetermined time and a predetermined frequency range, and therebyreceives or attempts to receive the beam scan signals 113. Since theuser device 112 does not know the direction toward the base station 111at this point, the user device 112 employs a non-directional receptiondistribution 114 to receive the beam scan signals 113, as indicated bythe dashed non-directional arcs. As mentioned, the beam scan signals 113are shown as solid lines indicating transmission distributions, whilethe reception distribution 114 is shown in dashed lines indicatingreception. In general, most of the transmitted beam scan signals 113 arelikely to be misdirected, resulting in zero or near-zero reception atthe user device 112, whereas one (or possibly two) of the beam scansignals 113 may be directed toward the user device 112, and those fewbeam scan signals may be detected with relatively high amplitude. Theuser device 112 may be configured to select the “best” beam scan signal113, having the best or highest quality reception, the highestas-received amplitude or power, or other measure of signal quality.

In some embodiments, each beam scan signal 113 may be a single resourceelement carrying a uniform sine wave transmission. Each beam scan signal113 may be identified, and the beam direction determined, according tothe time and frequency of each beam scan signal 113. If each beam scansignal 113 occupies a distinct time or frequency, that time-frequencyposition may be sufficient to enable the user device 112 to identifywhich of the transmission beams has the best reception. In that case, itmay not be necessary to encode further information in the beam scansignals 113, and therefore the beam scan signals 113 may be just asingle resource element. Each beam scan signal may be unmodulatedcarrier at the subcarrier frequency, or other signal, for example.However, all of the beam scan signals 113 preferably have the samesignal properties such as amplitude and phase, but different directions.The user device 112 can determine the time or frequency of theoptimally-received beam scan signal 113 by comparing the as-receivedamplitudes and determining at what time or frequency the best signal isobserved.

As an alternative, the base station 111 may transmit each beam scansignal 113 as two resource elements, or other number of resourceelements. For example, the beam scan signal with two resource elementsmay be modulated as a reference signal, such as a short-form two-pointdemodulation reference. When the beam scan signal includes multipleresource elements, the user device 112 may be able to obtain an improvedmeasure of the signal quality due to the additional measurement time. Ifthe beam scan signals are configured as demodulation references, theuser device may recalibrate the demodulation levels according to themodulation of the best-received beam scan signal 113, saving furthertime and resources.

After determining which beam scan signal 113 provides the best receptionquality, the user device 112 can then communicate that choice back tothe base station 111, as discussed below.

FIG. 1C is a schematic showing an exemplary embodiment of a reply signalfrom a user device to a base station, according to some embodiments. Asdepicted in this non-limiting example, a user device 122 transmits areply signal 124 to a base station antenna 121, responsive to the beamscan of the previous figure. The reply signal 124 is configured toindicate which of the beam scan signals 113 is selected for bestreception. The user device 122 transmits the reply signal 124non-directionally (as indicated by the solid curves 124) because theuser device 122 does not know the direction toward the base station 121at this point, and therefore cannot aim a transmission beam toward thebase station. The reply signal propagates to the base station 121 asindicated by an arrow 125. The base station is configured to monitor aparticular range of time and frequency during which the base station 121expects to receive the reply signal 124. The base station 121 uses anon-directional reception distribution 123 to receive the reply signalbecause the base station 121 does not know the direction toward the userdevice 122 at this point.

In some embodiments, the reply signal 124 may be a single resourceelement with a uniform sine wave transmission. The reply signal 124 maybe transmitted at a particular time or frequency. The time or frequencyof the reply signal 124 may correspond to the time or frequency of thebest-received beam scan signal 113. The reply signal 124 may therebyspecify which beam scan signal 113 is favored. For example, if the beamscan signals 113 are spaced apart in time, the user device can transmitthe reply signal 124 at a particular time which is a predetermined timedelay after the favored beam scan signal. Alternatively, if the beamscan signals 113 are transmitted in successive subcarriers at a singletime, the user device may transmit the reply signal 124 at the samesubcarrier or frequency as the favored beam. In either case, the basestation 121 can identify the selected beam 113 according to the time orfrequency of the reply signal 124.

In a first embodiment, the various beam scan signals 113 are transmittedsequentially in time, and the user device transmits the reply signal 124at a particular time corresponding to the selected beam's symbol-time.More specifically, each beam scan signal 113 may be transmitted insuccessive symbol-times of a first subframe (time-spanning), and theuser device 122 can transmit the brief reply signal 124 at the samesymbol-time of the next subframe (that is, a predetermined delay timelater). The base station 122 can determine, according to the timing ofthe reply signal 124, which of the beam scan signals 113 is favored. Ina second embodiment, the beam scan signals 113 are transmitted insequential subcarrier frequencies at the same symbol-time(frequency-spanning), and the user device 122 determines whichsubcarrier has the best signal. The user device then transmits the replysignal 124 on that same subcarrier at a subsequent agreed-upon time. Ineither case, the brief reply message 124, such as a single resourceelement, may be sufficient to inform the base station 121 of the userdevice's choice regarding the optimal beam direction.

In some cases, the user device 122 may find that two of the beam scansignals 113 provide nearly the same high level of reception. In thatcase, the user device 122 can transmit two reply messages 124,indicating the two best beam directions. As a further alternative, ifthe two best beam scan signals differ in their received signal quality,the user device can transmit two reply signals in adjacent resourceelements corresponding to the two favored beams, but with two differentamplitudes proportional to the two received amplitudes. The basestation, upon receiving the two reply messages at different amplitudes,can then interpolate between the two beam directions indicated, based onthe reply message amplitudes, and can use the interpolated beamdirection thereafter in communicating with the user device 122.

As another option, the user device can include further information inthe reply message by modulating the reply signal. For example, if thereply signal is modulated as QPSK, the phase may indicate furtherinformation. If yet more information transfer is needed, the replymessage may have two resource elements, or other number of resourceelements. The reply message may thereby convey a channel-stateinformation message, for example.

FIG. 1D is a schematic showing an exemplary embodiment of an alignmentmessage, transmitted from a base station to a user device, according tosome embodiments. As depicted in this non-limiting example, a basestation antenna 131 transmits an “alignment” message 133 directed towarda user device 132, using the user device's previously selected beamdirection 113. The alignment message 133 is a constant signal occupyingmultiple resource elements. The user device 132 can align its beamtoward the base station by varying its beam direction while receivingthe alignment message signals and determining which direction providedthe best reception. For example, the alignment message 133 may betransmitted by the base station 131 as a time-spanning message, insequential symbol-times at a particular subcarrier frequency, with allof the resource elements of the alignment message being identical intransmission direction and amplitude and phase. The alignment messagemay be transmitted non-directionally, or using the favored beamdirection of the user device as determined in the previous steps.

The alignment message propagates toward the user device 132 as indicatedby an arrow 135. The user device 132 then attempts to receive the eachresource element of the alignment message 133, while varying itsreception beam 134 across multiple directions. The user device therebymeasures the received amplitude using each of its reception beams 134sequentially, and can thereby determine which beam direction bestdetects the alignment message 133 signals. The user device 132 can thenuse that best beam direction thereafter for communicating with the basestation 131.

As an alternative, the user device 132 may be capable of preparingmultiple reception beams at the same time, on different subcarriers.(This is difficult, and requires digital beamforming.) If so, then thebase station 131 may transmit the alignment message 133frequency-spanning (in sequential subcarriers at the same symbol-time),instead of time-spanning (in successive symbol-times) as describedabove, and the user device 122 can determine which subcarrier providesthe best reception, and can thereby determine which of its receptionbeams to employ.

The user device 132 may determine that two adjacent reception beams 134provide similar high levels of signal quality. The user device 132 canthen use an intermediate reception beam direction by averaging, orweighted averaging, or interpolation, between the two favored receptionbeam directions.

As an option, the user device 132 may provide additional information inthe reply message 124, such as a CSI (channel state information) messageindicating the quality of the received signal. The reply message 124 mayoccupy more than one resource element in that case. For example, theuser device may measure the amplitude of the alignment message 133 inthe best or favored reception beam direction 134, and may report thatamplitude (or power level or SNR or other measure of signal quality)back to the base station 131 at that time.

FIG. 1E is a schematic showing an exemplary embodiment of anacknowledgement message from a user device to a base station, accordingto some embodiments. As depicted in this non-limiting example, the userdevice 142 transmits an acknowledgement message 145 directly toward thebase station 141 by using a transmission beam 144 aimed in the samedirection as the user device's favored reception beam 134. The userdevice thus assumes that the optimal transmission beam is in the samedirection as the optimal reception beam. Preferably the base station 141receives the acknowledgement message 144 using a narrow reception beam143, which is in the same direction as the favored transmission beam113, as determined during the initial beam scan of FIG. 1B. Reception ofthe acknowledgement message 145 thereby establishes the beamformed linkbetween the user device 142 and the base station 141.

In most cases, both entities can reduce their transmission power to alower level after configuring their beams, because the transmittedenergy is thereby focused into a narrow directional beam instead of anisotropic broadcast. For example, the base station can determine, fromthe amplitude or power level of the as-received acknowledgement message145, whether the user device 142 can obtain a satisfactory SNR if theuser device reduces its transmitted power, and if so, may instruct theuser device 142 to adjust its power level accordingly. In addition, theuser device may determine, from the reception of the continuous signal133, the signal amplitude (or SNR or received power etc.) in the userdevice's optimal reception beam 134, and may include an indication ofthat value in the acknowledgement message 145, or in a CSI accompanyingthe acknowledgement, for example. The base station 141, upon receivingthe CSI, may then lower its own transmission power on future messages tothat user device 142, in order to minimize background generation andinterference.

In some cases, the user device 142 may be incapable of beamforming. Inthat case, the alignment message 133 and the acknowledgement 144 may beskipped. The base station 131 may have previously determined whether theuser device 132 is capable of beamforming, for example in a messagetransmitted by the user device 132 upon joining the network.

In some embodiments, the beam scan signals 113, the reply message 125,and the alignment message 133 may be modulated according to a modulationscheme, and may thereby carry additional information.

In some embodiments, the beam scan signals 113 and/or the reply signal125 may include multiple resource elements, instead of a single resourceelement as described. Such longer signals may thereby convey additionalinformation.

In some embodiments, the user device 102 may indicate, in its requestmessage 105 or its reply signal 125 or its acknowledgement message 145,or otherwise, that the user device 102 is in motion, such as a vehicle.In that case, the base station 101 may provide wider beam widths in thebeam scan signals 113 than for a stationary user device. Wider beams mayavoid link failure due to the user device drifting out of a narrow beamdistribution.

In some embodiments, the roles can be reversed. The user device canperform the steps indicated above for the base station (such astransmitting beam scan signals in various directions), and the basestation can perform the steps indicated above for the user device (suchas selecting the beam that gives the best reception). Both entities canachieve mutual beam directionality, regardless of which one transmitsthe beam scan signals 113 and the alignment message 133.

In another embodiment, two user devices may use the disclosed proceduresto align their beams, without participation by a base station. Forexample, a pair of vehicles in traffic may use the procedures to adjusttheir reception and transmission beam directions.

In some cases, a reduced-capability user device may be unable to adjustdirectional transmission and reception beams, due to limitations in theuser device's small antenna, for example. However, such a user devicecan still assist the base station in determining the base station'soptimal beam direction for communicating with that user device byselecting the beam scan signal with the best reception, as indicated inFIG. 1B. Then, the reduced-capability device may skip or simply ignorethe step of adjusting the user device's receptivity beam in FIG. 1D. Thereduced-capability user device may continue to use non-directionalreceptivity 114 for communications thereafter, while the base stationcontinues to use beamformed transmissions and receptions whencommunicating with that user device.

Following is a second example, providing more detail about how areceiving device can measure signal amplitudes and thereby select theoptimal beam direction for both transmission and reception beams.

FIG. 2A is a sequence chart showing an exemplary embodiment of aresource-efficient transmission beam scan, from a base station to a userdevice, according to some embodiments. A sequence chart is a graphicshowing actions and signals from various entities versus time, which ishorizontal. As depicted in this non-limiting example, the procedure maybegin with a user device transmitting a request message 201 (dashed) toa base station, requesting beam adjustment service, or a base stationtransmitting a scheduling message 202 (dashed) specifying the time ofthe scan. Then base station transmits a plurality of beam scan signals203, each in a different direction, and then monitors the same frequencyduring a reply window 204 to detect a reply signal from the user device.In addition, optionally, the base station may transmit a start signal(not shown) which indicates to the user device that the beam scan isabout to begin. The request message 201 and scheduling message 202 areshown larger than the other signals to indicate that, in this case, therequest message 201 and the scheduling message 202 are transmittednon-directionally and at a higher power level than the others, so as toimprove reception while the entities are not yet able to use beamformingto enhance communication.

The beam scan 203 includes transmission of a plurality of beamformedsignals, each at a different transmission angle, each beam scan signalindicated by a small box, which in this case represents one resourceelement per beam transmission. Further resource elements 207 represent areply window 204 which is a region of time or frequency in which theuser device can transmit a reply signal 208 to the base station,indicating which beam scan signal 203 provided the best reception. Alsoshown in the third line is the received signal at the user device duringthe beam scan 203, with height representing received amplitude. Theamplitude is low at first, when the beam is not aimed toward the userdevice, and is highest when the beam is directed toward the user device,as indicated by a shaded resource element at best reception 205. Theuser device then waits a predetermined ΔT 206 after that peak amplitudeis detected, and then transmits the reply signal 208. In this case, thepredetermined delay ΔT 206 equals the duration of the beam scan 203.Hence, in this case, the reply window 204 begins immediately after thebeam scan 203 finishes. The user device transmits a brief reply signal208 after the delay time 206. The symbol-time of the reply signal 208thereby indicates, to the base station, which beam provided the bestreception. The base station receives the reply signal 208 during thereply window 204, determines the time of the reply signal 208, andthereby determines, from the specific time of the reply signal, which ofthe transmitted beams was selected by the user device. The base stationthen uses that selected beam direction for transmitting and receivingmessages with the user device thereafter. The base station assumes, inthis case, that the best reception beam is in the same direction as thebest transmission beam, as is commonly the case in wireless messaging.

FIG. 2B is a sequence chart showing an exemplary embodiment of aresource-efficient reception beam scan by a user device, according tosome embodiments. As depicted in this non-limiting example, the basestation transmits an alignment message 213 consisting of a plurality ofresource elements with all the same uniform signal therein and the samedirection. During the alignment message 213, the user device receivesthe alignment message while varying its reception beam direction,thereby determining which of the user device's internal antenna settingsresults in the best reception. There is no need for the user device toinform the base station of that choice, because it is an internalsetting of the user device; the base station simply provides the uniformsignals 213 on which the base station can test its reception directions.If the alignment message 213 is intended for just one user device, thebase station can transmit the alignment message 213 using the best beam205 direction, as determined in the previous example. However, ifmultiple user devices at different locations are aligning their antennadirections at the same time, it may be necessary for the base station totransmit the alignment message 213 non-directionally so that all of theuser devices can receive them.

On the third line is the received signal at the user device, as the userdevice varies its reception beam direction during the alignment message213. As shown, the received amplitude is maximum at the best reception215 direction, thereby enabling the user device to determine which beamdirection is aimed toward the base station. Then, after selecting theoptimal reception beam direction, and assuming that the optimaltransmission beam is the same as the optimal reception beam, the userdevice sets its antenna to transmit and receive messages from the basestation according to that selected beam at 216. (The user device beamadjustment 216 is an internal action of the user device, not atransmitted signal.) Then, the user device transmits an acknowledgement217 to the base station, preferably using the recently selectedtransmission beam direction. Optionally (not shown), the user device canalso transmit a channel-state information message indicating the signalquality received at the best reception beam setting 215.

FIG. 2C is a flowchart showing an exemplary embodiment of a procedurefor base stations and user devices to align their beams, according tosome embodiments. As depicted in this non-limiting example, at 251 abase station transmits a plurality of brief beam scan signals indifferent directions, all with the same amplitude and phase. The beamdirections may be around a plane, such as a horizontal plane, or theymay be three-dimensional, as when the base station is on a tower ormountain and the user devices are arrayed at ground level below, forexample.

At 252, the user device monitors the pre-scheduled channel frequency anddetects the beam scan signals, determining which beam scan signalprovides the best reception or signal quality at the user device. Theuser device notes the time or frequency, or both, of that best beam scansignal. Then, at 253, during a predetermined reply window, the userdevice transmits a brief reply signal at a time or frequencycorresponding to the time or frequency of the favored beam scan signal.For example, if the beam scan signals occupy sequential symbol-times atthe same subcarrier, then the reply signal may be transmitted at apredetermined time delay after the best-received beam scan signal; andif the beam scan signals are transmitted on sequential subcarriers, thereply signal may be at the subcarrier of the best-received beam scansignal, for example. In either case, the base station can determine, at253, which beam direction is preferred according to the time orfrequency of the reply signal. Extensive handshaking is neither desirednor required, saving considerable time and complexity.

Then, at 254, the base station may transmit an alignment messageconsisting of a plurality of resource elements all modulated the sameway and transmitted the same way. At 255, the user device attempts toreceive those signals by varying its (the user device's) reception beamdirection. The user device thereby determines the optimum beam directiontoward the base station.

In some embodiments, the beam scan signals are just one resource elementin size. In other embodiments, the beam scan signals may be two resourceelements, such as a short-form demodulation reference, or other numberof resource elements per beam direction. When multiple resource elementsare used in each beam scan signal, they may be configured astime-spanning or frequency-spanning. The parameters and configuration ofthe beam scan and alignment procedure may be specified in a systeminformation message or another message from the base station to the userdevices.

In some cases, the user device may be unable to do beamforming. Manylow-cost special-purpose devices, such as sensors, transmit and receivenon-directionally only. The user device may inform the base station ofits limitations upon joining the network, or at another time, in whichcase the base station may terminate the procedure after 253,determination of the best beam from the base station for that userdevice, and may skip the alignment message 254 and so forth.

Following is a third example, showing how the various beam messages maybe arranged time-spanning or frequency-spanning in a resource grid.

FIG. 3A is a schematic showing a resource grid with a resource-efficienttime-spanning beam selection message, according to some embodiments. Asdepicted in this non-limiting example, a resource grid of threesubframes 320 is demarked in subcarriers 322 and symbol-times 323, witha single resource element 321 indicated. A time-spanning beam scan 303is shown, each resource element having transmission in a differentdirection. Each transmission occupies a single resource element (onesymbol-time and one subcarrier) in this example. The beam scan signals303 are all identical, other than direction, so the user device cancompare them fairly.

The beam scan signals 303 are received by a user device, whichdetermines that a particular beam scan signal 305 (stippled) providesthe best reception. The user device waits a predetermined delay ΔT 306after the best reception is detected, and then transmits a reply signal308. In the meantime, the base station has completed the beam scan 303and has started monitoring the channel during a predetermined replywindow 304, and therefore detects the reply signal 308. In addition, thebase station can determine, from the time of the reply signal 308, whichbeam was selected. In this example, the delay time 306 equals onesubframe width, so the reply signal 308 occurs in the next subframe, butat the same symbol-time as the best reception 305. The base station canthereby determine which beam direction is preferred according to thesymbol-time of the reply signal 308, and can use that preferred beamdirection thereafter, for both transmission and reception ofcommunications with the user device.

At a predetermined time later, such as in the next subframe, the basestation transmits an alignment message 313 which is a series of resourceelements with the same transmission in each resource element. The userdevice, if it is capable of beamforming, can then attempt to receive thealignment message signals while varying its (the user device's)reception beam, and can thereby determine which reception beam directionprovides the best reception 315. The user device can then transmit andreceive messages with the base station using that best-reception beam315 thereafter.

After determining the best beam for the base station and the best beamfor the user device, the user device transmits an acknowledgement 317.The acknowledgement 317 is transmitted using the user device's besttransmission beam 315 for communications with the base station, and itis received by the base station using the base station's best receptionbeam 305 for communications with that user device. Thus the base stationand user device have both optimized their beam directions forcommunication with each other, while occupying a single subcarrier inthree subframes, in this example.

FIG. 3B is a schematic showing a resource grid with time-spanning beamalignment messages for multiple users, according to some embodiments. Asdepicted in this non-limiting example, a base station assists three userdevices in aligning both the base station beams and the user devicebeams. As before, the base station transmits a series of beam scansignals 333 in a sequence of symbol-times, however in this case eachbeam scan signal 333 has two resource elements in two subcarriers 335.For example, the beam scan signals 333 may be short-form two-pointreferences that exhibit the maximum and minimum values (such asamplitudes and/or phases) of a modulation scheme, or other informationthat can be packed into two resource elements 335.

The three user devices transmit their reply messages in a reply window334 in the next subframe, with each user device assigned a differentsubcarrier of the reply window 334. Thus the first user device transmitsa reply signal 338 indicating which beam direction is most stronglyreceived at that user device, and the third user device transmits adifferent reply message 339 at a different time of the reply window,indicating a different beam direction preference. The second user devicetransmits two reply messages 336 and 337, thereby indicating that bothof the corresponding beam scan signals provided similar high signalquality. The base station, upon detecting the two reply signals 336, 337can then use a beam direction between those two beams, such as half-waybetween them.

The three user devices then align their own beams toward the basestation using the alignment message 343. In this case, the base stationtransmits three alignment messages in three directions to the three userdevices, using the base station beam directions that were selected inthe reply windows 334. During the alignment messages 343, the userdevices can vary their own reception beam directions to optimize theamplitude or signal quality of the received signals.

Finally the three user devices transmit acknowledgement messages 347,348, 349 using their aligned beams toward the base station.

FIG. 3C is a flowchart showing an exemplary embodiment of atime-spanning procedure for base stations and multiple user devices toalign their beams, according to some embodiments. As depicted in thisnon-limiting example, at 351 a base station transmits a series of briefbeam scan signals at different directions in successive symbol-times,while one or more user devices attempt to receive those signals anddetermine which beam provides the best signal quality. Then at 352, theuser devices transmit reply messages at a time corresponding to theirfavored beam scan signal, but on the subcarrier assigned to each of theuser devices, so as to avoid contention and interference. At 353, thebase station transmits alignment messages, one for each of the userdevices, on separate subcarriers (which may be the same subcarriersassigned for the reply messages), and directed according to thepreviously selected beam directions from the base station. The userdevices vary their reception beam directions while attempting to receivethe alignment message, and thereby determine which local beam directionbest communicates with the base station.

FIG. 4A is a schematic showing an exemplary embodiment of an efficientfrequency-spanning beam selection, according to some embodiments. Asdepicted in this non-limiting example, a resource grid 420 includesfrequency-spanning messages similar to the time-spanning messages of theprevious examples. Frequency-spanning beam alignment messages providelower latency than time-spanning. Frequency-spanning and time-spanningmessages both occupy the same number of resource elements. As mentioned,frequency-spanning alignment messages generally place greater demands onthe user device's signal processing electronics than time-spanning. Afrequency-spanning beam scan, on the other hand, places demands on thebase station including digital beamforming, but should be relativelysimple for the user device to detect and analyze.

For user devices that can handle frequency-spanning alignment messages,the example provides specifics. First, the figure shows afrequency-spanning beam scan 403. The beam scan 403 is demarked by anon-directional scan-start signal 402. The beam scan 403 appears thesame as an ordinary 5G/6G frequency-spanning message, and therefore userdevice receiver can receive and interpret the beam scan 403 in the usualway. The user device can thereby determine which subcarrier has the bestsignal reception 405. The user device can then inform the base stationof the favored beam, by transmitting a brief (one resource element inthis case) reply signal 408 during a predetermined reply window 404. Theuser device transmits the reply signal 408 on the same subcarrier 406 asthe best reception of the beam scan 403, thereby indicating which beamthe user device favors. The base station can determine, according to thesubcarrier of the reply message 408, which transmission beam to use forfurther communication with the user device.

At a predetermined time later, the base station transmits an alignmentmessage 413 toward the user device, using a transmission beam in thedirection determined according to the reply signal 408. No start pulseis transmitted before the alignment message 413 in this case, since theuser device is expected to know the position of the alignment messagerelative to the reply window 404, or relative to the beam scan 403. Thealignment message 413 is a number of resource elements, arrangedfrequency-spanning, transmitted by the base station with all the samesignal in each resource element of the alignment message 413. The signalmay be unmodulated carrier at each subcarrier frequency, or a modulatedsignal, for example. The user device can then vary its reception beamdirection, different for each resource element of the alignment message413, and can thereby determine which direction, relative to the userdevice, provides the best reception 415. The user can then use atransmission beam in the same direction to communicate with the basestation.

At another predetermined time later, the user device transmits, to thebase station, using the user device's best reception beam fortransmission, an acknowledgement 416 and, in this case, a channel stateinformation message 417 based on the signal quality observed by the userdevice during the alignment message 413 at the best reception direction415. The base station, detecting the CSI 417, can then adjust its (thebase station's) power level when transmitting to the user device,thereby providing sufficient reliability without excess transmissionpower. In addition, the base station can advise the user device as toits (the user device's) power level, based on the amplitude received bythe base station for the acknowledgement 416 and/or the CSI 417.

FIG. 4B is a schematic showing an exemplary embodiment of an efficientfrequency-spanning beam selection for multiple users, according to someembodiments. As depicted in this non-limiting example, at a scheduledtime, a base station transmits a plurality of beam scan signals 433 atdifferent directions on successive subcarriers, while a plurality ofuser devices (three, in this case) receive the beam scan signals 433,separate them using signal processing, and determine which of the beamsprovides the best reception. Then, at pre-assigned reply window 434symbol-times, the three user devices transmit their reply signals 438,on the same subcarriers as the favored beam scan signals for each userdevice. The base station, receiving the three reply signals 438 anddetermining which of the beams are associated with which reply signals438, can use those beams thereafter for communicating with the userdevices specifically, that is, unicast and beamformed.

The base station then assists the user devices in aligning their ownbeams toward the base station by broadcasting an alignment message 443including a plurality of resource elements arranged frequency-spanning.However, in this case the alignment message is not transmitted using thefavored beam directions of each user device, but instead is broadcastnon-directionally so all can receive it. In another embodiment, if thebase station has sufficient beamforming flexibility, the base stationmay configure the alignment message to have multiple peak directionswith one peak power direction toward each of the three user devices. Forexample, the base station can digitally add the antenna configurationsfor each of three separate beams toward the user devices, and therebygenerate a three-peaked emission pattern. The user devices then receivethe alignment message 443 by applying a different antenna reception beamfor each subcarrier of the alignment message 443, and thereby determinetheir own best beam directions toward the base station. Finally, theuser devices, using their transmission beams aimed at the base station,transmit three acknowledgement messages 446 and three channel-stateinformation messages 447, on three pre-assigned symbol-times.

FIG. 4C is a flowchart showing an exemplary embodiment of afrequency-spanning procedure for base stations and multiple user devicesto align their beams, according to some embodiments. As depicted in thisnon-limiting example, at 451 a base station transmits multiple briefsignals on successive subcarriers, each signal in a different direction,while user devices receive and measure the signals to determine whichdirection is best received. At 452, user devices transmit, in apre-assigned reply window, a brief reply message indicating, by thesubcarrier of the reply message, which subcarrier of the beam scan wasbest received, and thereby inform the base station which beam to use incommunicating with each of the user devices. At 453, the base stationtransmits a plurality of uniform signals on success subcarriers. Thealignment signals may be transmitted non-directionally, or they may betailored to have transmission maxima aimed at the various user devices,depending on the implementation. During the alignment message, the userdevices vary their reception beam directions, aiming differently duringeach subcarrier of the alignment message, and thereby determine thecorrect beam direction for communicating with the base station.

It may be noted that transmitting the beam scan signals 433 in multipledirections on successive subcarriers, all simultaneously, puts greatdemands on the base station electronics. Also stressful is configuringthe transmission of the alignment message elements to be directed towardmultiple different directions at the same time, that is, a multi-peakedangular distribution of transmitted power. However, some base stationsin the coming 5G rollout are expected to have digital antenna controls,and may be able to do exactly that. In addition, the frequency-spanningalignment message 443 puts great demands on the user devices, since theymust vary their reception beams on successive subcarriers all at thesame time. Some sophisticated user devices may be able to handle it, butmost user devices probably will not, at least for the foreseeablefuture. Therefore, the example is for the most capable wireless systems.The following figures are for less capable user devices.

FIG. 5A is a schematic showing an exemplary embodiment of aresource-efficient frequency-spanning and time-spanning beam selection,according to some embodiments. As depicted in this non-limiting example,a resource grid 520 includes both frequency-spanning and time-spanningmessages, to accommodate a user device that cannot vary its receptionbeam in multiple directions at sequential subcarriers at a singlesymbol-time. As in the previous example, the base station transmits abeam scan 503 frequency-spanning, and the user device can determine thata particular subcarrier 505 provides the best reception. Then, during afrequency-spanning reply window 504, the user device transmits a replysignal 508 at the same subcarrier 506 as the best reception beam 505.

In this case, the user device cannot receive multiple beam directionssimultaneously. Therefore, the base station provides an alignmentmessage 513 time-spanning as shown, instead of frequency-spanning. Theuser device can vary its reception beam successively, during eachsymbol-time of the alignment message 513, and can thereby determine thata particular beam direction 515 provides the best reception. Then, usingthat best quality beam direction, the user device can transmit anacknowledgement 516 and a CSI 517 to the base station. Thus the basestation and the user device have aligned their beams toward each other,while allowing the user device to avoid the difficult task of arrangingmultiple reception beam directions in separate subcarriers at a singletime.

FIG. 5B is a schematic showing another exemplary embodiment of anefficient frequency-spanning beam selection for multiple users,according to some embodiments. As depicted in this non-limiting example,a base station transmits a beam scan 533 frequency-spanning, and threeuser devices determine thereby which beam provides the best reception.Then during an assigned reply window 534, each user device transmits areply signal 538 at the subcarrier of the favored beam scan signal,thereby informing the base station which beams to use when communicatingwith those user devices. Then the base station transmits an alignmentmessage 543, but his time the alignment message 543 is time-spanning insuccessive symbol-times, so that the user devices can test theirreception beams successively in time on the alignment message elements.This is very much easier for a user device to do, than varying thedirection of reception in different subcarriers simultaneously asdescribed above. The user devices can thereby determine their ownoptimal direction toward the base station.

FIG. 5C is a flowchart showing an exemplary embodiment of a simplerprocedure for base stations and multiple user devices to align theirbeams, according to some embodiments. As depicted in this non-limitingexample, at 551 a base station transmits multiple brief beam scansignals frequency-spanning, on successive subcarriers, and the userdevices determine which beam signal is best received. At 552, the userdevices transmit brief reply signals at a pre-assigned symbol time andon whichever subcarrier held the best-received beam scan signal, therebyinforming the base station which beam direction each user deviceprefers. At 553, the base station transmits an alignment messagenon-directionally and time-spanning, which the user devices detect usinga variety of reception beams, and thereby determine their own properdirection toward the base station. No acknowledgement is needed becausethe reply messages served that purpose, and no channel-state informationmessages are needed because the alignment message was transmittednon-directionally, and therefore is not a realistic measure of the basestation link to the user devices. At some later time, the user devicescan provide channel state information separately.

Following is a fourth example showing steps in a procedure to alignnetwork beam directions.

FIG. 6 is a flowchart showing an exemplary embodiment of a procedure foraligning beam directions, according to some embodiments. As depicted inthis non-limiting example, a user device of a network that includes abase station can transmit, at 601, a beam-selection request messagerequesting beam alignment service. The user device and the base stationdo not know each other's locations at that time, so the user devicetransmits the request message non-directionally and at a high powerlevel, while the base station receives the request message using anon-directional antenna setting.

Alternatively, at 602, the base station can initiate the process bytransmitting a beam-selection scheduling message to the user device,thereby scheduling the alignment service. The base station may transmitthe scheduling message non-directionally and at high power, while theuser device can receive the scheduling message using a non-directionalantenna setting.

In either case, at 603, the base station transmits a series of briefsignals sequentially, on multiple beam directions. In one version, thebase station can transmit the brief beam scan signals sequentially intime at a single subcarrier frequency (time-spanning). In the otherversion, the base station can transmit the beam scan signalssequentially on multiple subcarriers at a single symbol-time(frequency-spanning). In either version, the user device, at 604,measures the signal quality for each of the resource elements of thebeam scan signals, and determines which of the received beam signalsprovides the best amplitude (or SNR or other measure of signal quality).The user device may note the symbol-time of the best-quality beam signal(if time-spanning), or the best-reception subcarrier (iffrequency-spanning).

The user device then informs the base station of which beam provides thebest signal. The user device does so by transmitting a brief (such as asingle resource element) signal within a reply window that is previouslydefined by the base station. The manner of transmitting the reply signaldepends on whether the beam scan signals were transmitted time-spanningor frequency-spanning. At 605, the beam scan signals were ordered orsequenced in time, so the user device indicates the favored beam bytransmitting a brief reply signal 606 at a particular time correspondingto the time of the best-quality beam signal. The base station detectsthe reply signal at that particular time and at 608 determines whichbeam direction was selected by the user device. The base station maymonitor a previously-reserved reply window of sequential symbol-times,each resource element of the reply window having a one-to-onecorrespondence with the symbol-times of the beam scan signals, andthereby determines which beam direction to use in communicating with theuser device.

Alternatively, if the beam scan signals are sequential in frequency at605, the reply window is a set of subcarriers at a single symbol-time,each subcarrier of the reply window matching the correspondingsubcarrier of the beam scan signal, in this embodiment. The user devicethen informs the base station of the preferred beam by transmitting abrief reply signal 607 to the base station at the particular frequency(subcarrier) which corresponds to the frequency of the best-quality beamsignal. The base station determines 609 which beam direction wasselected by the user device, according to the frequency of the replysignal. More specifically, the base station monitors apreviously-reserved reply window, the reply window having sequentialsubcarriers at a particular symbol-time. Thus there is a one-to-onecorrespondence between the subcarriers of the beam scan signals and thesubcarriers of the reply window. The base station can thereby determinewhich beam direction is preferred by the user device.

The example also includes procedures for the user device to align itstransmission and reception beams toward the base station, if the userdevice is capable of beamforming. At 610, the base station determines(or already knows) whether the user device is capable of beamforming. Ifso, at 611 the base station transmits an alignment message consisting ofmultiple resource elements, all transmitted identically with the samesignal and same direction toward the user device. The alignment messagemay be time-spanning or frequency-spanning, depending on thecapabilities of the user device. Frequency-spanning alignment isdifficult because the user device would need to detect multiple beamdirections in sequential subcarriers at the same time, a challenge formost user devices. In this example the alignment message is assumed tobe time-spanning.

At 612, the user device receives the alignment message while varying itsreception beam to multiple directions, and thereby determines whichreception direction provides the best signal quality. At 613, the userdevice transmits an acknowledgement to the base station using atransmission beam direction equal to the optimal reception beamdirection determined at 612. Also, the base station receives theacknowledgement using a reception beam, at the base station, equal tothe selected optimal transmission beam determined at 608 or 609. At thatpoint, both entities are aligned with each other.

Optionally (in dash), at 614, the user device can transmit achannel-state information message indicating the signal quality receivedby the user device. For example, the user device can evaluate the finalsignal quality based on the signal received from the beam selectionsignal (at 604) if the user device does not use beamforming, or from thealignment signal (at 612) if it does use beamforming. The base stationcan then instruct the user device to adjust its transmission poweraccording to the observed signal quality, to avoid wasting energy andgenerating unnecessary background. In addition, the base station canadjust its own transmission power, for future communication with theuser device, based on the signal quality received by the base station onthe reply message (at 608 or 609) or the acknowledgement message (at613). After aligning their transmission and reception beams, the basestation and the user device may be able to use less transmission powerwithout loss of reliability, thereby saving energy and reducingbackgrounds.

The foregoing example provided separate messaging for the base stationand user device to align their respective beams. In the followingexamples, the alignment step is avoided. After the user device selectsthe best beam scan signal direction, the base station then transmits amessage to the user device indicating the compass direction of theoptimal beam toward the user device, as selected by the user device'sreply message. With that geographical direction information, the userdevice can set its own beam toward the base station by adding orsubtracting 180 degrees to the base station's compass measurement.Setting the user device's beam opposite to the base station's beam maybe simpler than using the alignment message procedure, but it requiresthe user device to have a compass or otherwise determine geographicaldirections. In addition, the beam between the base station and the userdevice is assumed to be nearly line-of-sight with no large-anglereflections.

FIG. 7 is a schematic showing a resource grid with resource-efficientbeam selection and direction messages, according to some embodiments. Asdepicted in this non-limiting example, a resource grid 720 includes afrequency-spanning beam scan 703 including multiple frequency-spanningresource elements, each beam scan resource element containing a signaltransmitted in a different directions. The user device can receive thebeam scan 703, determine which subcarrier provides the best signal 705(stippled) and then reply 708 in a predetermined reply window 704(ghosted) using the same subcarrier 706 as the best reception 705signal.

To assist the user device in directing a beam back toward the basestation, the base station transmits a geographical direction message713. This is instead of an alignment message. In the geographicaldirection message 713, the base station indicates the geographicaldirection of the base station's beam 705 selected by the user device.The user device can then adjust its own beam toward the base station byadding or subtracting 180 degrees to the angle indicated in thegeographical direction message 713. The user device can thereby alignits beam toward the base station without an alignment message (assumingthe user device has a compass or other means for determininggeographical directions). The user device then sends an acknowledgement717 to the base station, using that calculated beam direction. If theuser device is not equipped with an electronic compass or equivalent,then the user device can decline to transmit the acknowledgement 717.Alternatively, if the user device has a compass and transmits theacknowledgement message 717, but in fact the beam path is bent due to areflection, then the base station is unlikely to receive theacknowledgement 717 since it will be aimed in the wrong direction, dueto the reflection. In either case, the base station would fail toreceive an acknowledgement, and therefore may transmit an alignmentmessage as discussed previously, so that the user device can align itsbeam toward the base station despite the reflection or the lack ofcompass.

FIG. 8 is a flowchart showing an exemplary embodiment of a procedure foraligning beam directions based on geographical directions, according tosome embodiments. As depicted in this non-limiting example, thealignment message is replaced by a geographical direction message,enabling the user device to align its beam toward the base station. At801, the base station transmits a series of beam scan signals onsuccessive symbol-times or subcarriers, each with a different beamdirection. At 802, the user device measures the received signal qualityfor each of the beam scan signals and determines which one provides thebest signal quality. At 803, the user device transmits a brief replysignal at a time and frequency corresponding to the selected beam scansignal. At 804, the base station determines, from the timing orfrequency of the reply signal, which beam provides the best receptionwith the user device, and notes the geographical direction (such as acompass direction in degrees, for example) of the favored beam. The basestation then transmits a “geographical direction” message to the userdevice, on the selected beam direction, indicating the geographicaldirection of the selected beam toward the user device. At 805, the userdevice receives the geographical direction message, adds or subtracts180 degrees, determines (based on an internal compass, for example)geographical north, and sets its own beam toward the base station in thecalculated direction. Then, using that beam setting, the user devicetransmits an acknowledgement to the base station. At 806, if the basestation fails to receive the acknowledgement message (due to lack ofcompass, reflected beam path, or other mishap), the base stationtransmits an alignment message as discussed previously, and the userdevice can vary its reception beam direction to determine whichdirection provides the best reception of the alignment message, therebycompleting the mutual beam alignment.

Optionally (not shown), the base station can use the selected basestation beam to receive the acknowledgement message, and can measure thesignal strength received thereby, and determine whether the user devicecan safely reduce the transmission power without loss of reliability.The base station can then transmit a power-adjustment message to theuser device. Optionally (not shown), the user device can measure thesignal quality received in the power-adjustment message and transmit aCSI back to the base station, so that the base station can adjust itsown transmission power accordingly.

The following examples show procedures for a reduced-capability userdevice, which lacks beamforming capability, to assist the base stationin aligning the base station's beam.

FIG. 9 is a schematic showing a resource grid with a resource-efficientbeam selection for user devices that lack beamforming, according to someembodiments. As depicted in this non-limiting example, a base stationaligns its beam toward a user device, but the user device has nobeamforming capability itself, and therefore the alignment message stepis skipped. A resource grid 920 includes a frequency-spanning beam scan903 including multiple resource elements with the base stationtransmitting signals in different directions for different subcarriers.The user device can receive the beam scan 903, determine whichsubcarrier provides the best signal 905, stippled, and then reply in apredetermined reply window 904 (ghosted) using the same subcarrier 906as the best reception 905 signal. However, in this case the reply signal908 is configured as a CSI message indicating the signal qualityreceived by the user device in that best-quality beam scan signal 905.To accommodate the size of the CSI message, the reply window 904 is madelonger in time, including a sufficient number of symbol-timescorresponding to the number of bits in the CSI 908. The figure shows tworesource elements in the CSI, but a different number of resourceelements may be needed, depending on the modulation. If so, the replywindow 904 may be made wide enough to accommodate by adding moresymbol-times to the reply window. The base station, receiving the CSI908, can do two things. First, the base station can adjust its own powerlevel according to the signal quality reported in the CSI 908. There isno reason to waste energy and generate backgrounds by transmittinghigher power levels than needed for reliable reception. Secondly, thebase station can determine, from the signal quality of the as-receivedCSI message 908, what power level the user device should be using, andmay transmit a power-adjustment message 917 to the user device for thatpurpose. Preferably, the base station transmits the power-adjustmentmessage 917 using the selected beam 905. Thus the base station hasaligned its beam toward the user device, and the user device hasadjusted its power levels accordingly. There is no alignment message orthe like, because in this case the user device has no beamformingcapability.

In another embodiment, the base station may not be prepared to transmitmultiple beam directions on successive subcarriers at a single time,that is, the frequency-spanning beam scan 903. In that case, the basestation can transmit the beam scan 903 as time-spanning, and can reservethe reply window 904 as time-spanning but with two subcarriers, to stillprovide two resource elements for the CSI (or whatever number ofresource elements it requires in a particular embodiment).

FIG. 10 is a flowchart showing an exemplary embodiment of a procedurefor user devices that lack beamforming, according to some embodiments.As depicted in this non-limiting example, the alignment message isskipped because the user device has no beamforming capability. At 1001,the base station transmits a series of beam scan signals on successivesymbol-times or subcarriers, each with a different beam direction. At1002, the user device measures the received signal quality for each ofthe beam scan signals and determines which one provides the best signalquality. At 1003, the user device transmits a CSI message at a time andfrequency corresponding to the selected beam scan signal. At 1004, thebase station determines, from the timing or frequency of the CSI replysignal, which beam provides the best reception with the user device. Thebase station adjusts its own power level, for future transmission to theuser device, based on the values provided in the CSI message, to avoidusing excessive power when it is not needed. The base station alsomeasures the as-received beam quality of the CSI message itself, and at1004 transmits a power-adjustment message to the user device instructingthe user device what power level to use in future communications withthe base station.

The systems and methods disclosed herein may enable base stations andwireless devices to align their transmission and reception beams towardeach other in a managed network. In a non-managed network such as an adhoc network among mobile user devices, the communicating entities canalign their beams in the same way, with one of the mobile user devicestemporarily assuming the role of the base station, for example.

The systems and methods may enable wireless devices to align theirreception and transmission beam directions quickly and efficiently, withlittle consumption of resource elements. The systems and methods maythereby provide improved communication reliability with less energyconsumption and less background generation, thereby enhancing networkfunction and user satisfaction overall.

The wireless embodiments of this disclosure may be aptly suited forcloud backup protection, according to some embodiments. Furthermore, thecloud backup can be provided cyber-security, such as blockchain, to lockor protect data, thereby preventing malevolent actors from makingchanges. The cyber-security may thereby avoid changes that, in someapplications, could result in hazards including lethal hazards, such asin applications related to traffic safety, electric grid management, lawenforcement, or national security.

In some embodiments, non-transitory computer-readable media may includeinstructions that, when executed by a computing environment, cause amethod to be performed, the method according to the principles disclosedherein. In some embodiments, the instructions (such as software orfirmware) may be upgradable or updatable, to provide additionalcapabilities and/or to fix errors and/or to remove securityvulnerabilities, among many other reasons for updating software. In someembodiments, the updates may be provided monthly, quarterly, annually,every 2 or 3 or 4 years, or upon other interval, or at the convenienceof the owner, for example. In some embodiments, the updates (especiallyupdates providing added capabilities) may be provided on a fee basis.The intent of the updates may be to cause the updated software toperform better than previously, and to thereby provide additional usersatisfaction.

The systems and methods may be fully implemented in any number ofcomputing devices. Typically, instructions are laid out on computerreadable media, generally non-transitory, and these instructions aresufficient to allow a processor in the computing device to implement themethod of the invention. The computer readable medium may be a harddrive or solid state storage having instructions that, when run, orsooner, are loaded into random access memory. Inputs to the application,e.g., from the plurality of users or from any one user, may be by anynumber of appropriate computer input devices. For example, users mayemploy vehicular controls, as well as a keyboard, mouse, touchscreen,joystick, trackpad, other pointing device, or any other such computerinput device to input data relevant to the calculations. Data may alsobe input by way of one or more sensors on the robot, an inserted memorychip, hard drive, flash drives, flash memory, optical media, magneticmedia, or any other type of file—storing medium. The outputs may bedelivered to a user by way of signals transmitted to robot steering andthrottle controls, a video graphics card or integrated graphics chipsetcoupled to a display that maybe seen by a user. Given this teaching, anynumber of other tangible outputs will also be understood to becontemplated by the invention. For example, outputs may be stored on amemory chip, hard drive, flash drives, flash memory, optical media,magnetic media, or any other type of output. It should also be notedthat the invention may be implemented on any number of different typesof computing devices, e.g., embedded systems and processors, personalcomputers, laptop computers, notebook computers, net book computers,handheld computers, personal digital assistants, mobile phones, smartphones, tablet computers, and also on devices specifically designed forthese purpose. In one implementation, a user of a smart phone orWi-Fi-connected device downloads a copy of the application to theirdevice from a server using a wireless Internet connection. Anappropriate authentication procedure and secure transaction process mayprovide for payment to be made to the seller. The application maydownload over the mobile connection, or over the Wi-Fi or other wirelessnetwork connection. The application may then be run by the user. Such anetworked system may provide a suitable computing environment for animplementation in which a plurality of users provide separate inputs tothe system and method.

It is to be understood that the foregoing description is not adefinition of the invention but is a description of one or morepreferred exemplary embodiments of the invention. The invention is notlimited to the particular embodiments(s) disclosed herein, but rather isdefined solely by the claims below. Furthermore, the statementscontained in the foregoing description relate to particular embodimentsand are not to be construed as limitations on the scope of the inventionor on the definition of terms used in the claims, except where a term orphrase is expressly defined above. Various other embodiments and variouschanges and modifications to the disclosed embodiment(s) will becomeapparent to those skilled in the art. For example, the specificcombination and order of steps is just one possibility, as the presentmethod may include a combination of steps that has fewer, greater, ordifferent steps than that shown here. All such other embodiments,changes, and modifications are intended to come within the scope of theappended claims.

As used in this specification and claims, the terms “for example”,“e.g.”, “for instance”, “such as”, and “like” and the terms“comprising”, “having”, “including”, and their other verb forms, whenused in conjunction with a listing of one or more components or otheritems, are each to be construed as open-ended, meaning that the listingis not to be considered as excluding other additional components oritems. Other terms are to be construed using their broadest reasonablemeaning unless they are used in a context that requires a differentinterpretation.

The invention claimed is:
 1. A method for a base station of a wirelessnetwork to align a beam from the base station to a user device of thenetwork, the method comprising: a. transmitting a plurality of beam scansignals, each beam scan signal comprising a wireless transmissionfocused in a different direction, the beam scan signals spaced apart intime or in frequency; b. receiving, from the user device, a reply signalindicating a particular beam scan signal, the reply message comprising awireless transmission at a time corresponding to a time of theparticular beam scan signal or at a frequency corresponding to afrequency of the particular beam scan signal; and c. transmitting, tothe user device, a subsequent message directed according to theparticular beam scan signal; d. wherein the subsequent message comprisesan alignment message comprising a plurality of alignment messageelements, wherein all of the alignment message elements are transmittedwith the same amplitude, phase, and spatial distribution.
 2. The methodof claim 1, wherein the beam scan signals are transmitted according toat least 5G technology.
 3. The method of claim 1, wherein the particularbeam scan signal provides higher signal quality than any other beam scansignal, wherein signal quality comprises a received amplitude or areceived power level or a received signal-to-noise ratio at the userdevice.
 4. The method of claim 1, wherein each beam scan signalcomprises exactly one resource element, and the reply signal comprisesexactly one resource element.
 5. The method of claim 1, wherein eachbeam scan signal comprises two resource elements configured as ademodulation reference, and the reply signal comprises a channel-stateinformation message.
 6. The method of claim 1, wherein the beam scansignals are spaced apart in time, and the reply signal is received at apredetermined delay time after the particular beam scan signal.
 7. Themethod of claim 1, wherein the beam scan signals are spaced apart infrequency, and the reply signal is received at the same frequency as theparticular beam scan signal.
 8. The method of claim 1, furthercomprising indicating, to the user device, a reply window comprising aplurality of resource elements, and receiving the reply signal withinthe reply window.
 9. The method of claim 1, wherein the beam scansignals are spaced apart in frequency and the alignment message elementsare spaced apart in time.